Penn Medicine contributes substantially to the local economy. In 2008, Penn Medicine created 37,000 jobs and $5.4 billion in regional economic activity, with the area's highly trained workforce producing more than 24,600 applications for just 840 open Penn staff research positions. The current proposal will create or retain 5 jobs at two different institutions. This is an application for a Competitive Revision to 1R01-CA90744: "Aldo-Keto Reductases and Nuclear Receptor Action" (Project End Date: 06/30/12) to be funded by the American Recovery and Reinvestment Act of 2009. The parent grant is focused on the role of AKR1C3 (type 5 17[unreadable]-hydroxysteroid dehydrogenase (17[unreadable]-HSD) or prostaglandin F synthase) in regulating the local production of ligands for nuclear receptors in prostate and breast cancer. Our hypothesis is that prostate cancer is a disease of the aging male and that it is driven by the local production of androgens in the gland rather than by androgens of testicular origin. The precursor for this intracrine formation of androgens is likely dehydroepiandrosterone of adrenal origin or pregnenolone of prostatic origin. AKR1C3 plays a key role in prostate androgen biosynthesis since it converts ?4-androstene-3,17-dione (a weak androgen) to testosterone (a potent androgen) and lies immediately upstream from type 2 5a-reductase. Recently, castration resistant prostate cancer has been shown to undergo a re-programming of androgen biosynthesis due to androgen deprivation. Part of this response includes upregulation of several genes involved in androgen biosynthesis including AKR1C3. Moreover, abiraterone acetate a CYP17,20-lyase inhibitor has been found effective in advanced prostate cancer suggesting that local androgen signaling may still be occurring. To test this hypothesis it is critical to have reliable methods to measure intraprostatic androgen levels in different patient groups and relate them to enzyme expression levels. This supplement will therefore go beyond the initial funded specific aims of the grant to: [1] Develop a stable-isotope dilution LC/MS assay for the detection and quantitation of all androgen metabolites downstream from pregnenolone and dehydroepiandrosterone (DHEA);[2] Validate the method by measuring androgen metabolic profiles in LNCaP and LNCaP-AKR1C3 stably transfected cells;[3] Apply the method to measure intrapostatic androgen levels in adenocarcinoma of patients that have undergone radical prostatectomy (positive control) and adjacent normal tissue;and in prostatectomy samples in patients that underwent different androgen deprivation therapies prior to surgery, e.g. LHRH agonist alone;LHRH agonist + bicalutamide (androgen receptor antagonist);and LHRH agonist + bicalutamide + ketoconazole (a CYP17,20- lyase inhibitor);and [4] Use qPCR to measure the expression of all steroidogenic enzymes after cholesterol in the same prostate specimens: Scc, CYP17A1, HSD3B2, AKR1C3, SRD5A1, SRD5A2, AKR1C2, AKR1C1, HSD17B2, HSD17B6, and UGT2B15 to determine if their levels correlate with the androgen levels observed. These studies will lead to a robust method that can measure intraprostatic androgen levels in prostate cancer patients that have undergone radical prostatectomy and determine the efficacy of androgen deprivation therapy. They will also determine whether prostatic androgen synthesis can occur from pregnenolone and whether elevated androgen levels can be correlated to increased expression of steroidogenic enzymes including AKR1C3. PUBLIC HEALTH RELEVANCE: Prostate cancer is the second leading cause of cancer death in man. It is initially responsive to androgen ablative therapy but thereafter patients relapse and develop castration resistant prostate cancer (CRPC). Emerging data suggests that CRPC has undergone a re-programming or adaptive response to androgen ablation and synthesizes its own androgens. Aldo-keto reductase (AKR) family 1C member 3 (AKR1C3) also known as type 5 17[unreadable]-hydroxysteroid dehydrogenase may play a key role in this response. This proposal is aimed at developing a stable isotope dilution liquid chromatography mass spectrometry method to measure the intraprostatic androgen metabolome which could be used to better diagnose and treat prostate cancer.